Alarm for pneumatic tires.



JOSEPH B. POLO, 0! CLEAR LAKE, SOUTH DAKOTA.

ALARM FOR PNEUMATIC TIRES.

Specification of Letters Patent.

Application filed January 4, 1913.

Patented Mar. 24, 1914.

Serial No. 740,249.

To all whom it may concern:

Be it known that I, JOSEPH B. PoLo, a

citizen of the United States, residing at following is a specification,reference being had to'the. accompanying drawings.

This'invention comprehends certaln new and useful improvements in alarmsfor pneumatic tires, and has for its primary object to provide an alarmwhich w1l1 g1ve an audible signal when the pressure within thetireincreases or decreases below predetermined points.

Another object is to provide a device of this character which will beautomatic in operation and which will be of comparatively simpleconstruction.

Another object is to provide a device of this character which may beregulated to vary the operation of the parts thereof and thereby set thedevice to give the signal upon the decrease or increase of the airpressure within the tire above or below. any point desired.

A further object is to construct a device of this character which may beregulated to give the signal, upon either an increase or decrease ofpressure in the tire,

or simply upon the decrease of pressure, as desired.

and e'ifective in the performance of its duties.

' With the above and other objects in view, this invention consists incertain novel details of construction, combination and arrangementofparts to be hereinaftermore fully described, claimed, and particularlypointed out in the accompanymgdrawmgs, in which- Figure 1 is alongitudinal section through my complete device applied to an ordinaryvalve stem. Fig. 2 is an elevational view of the same. Fig. 3 is adetail cross sec tional view on the line 3- 3 of Fig. 1.; Rig. 4: is afragmentary longitudinal section through the first and second cylindersand through the check valve 30 and valve seat 30.

Referring more particularly to the drawings, in which similar referencecharacters designate corresponding parts throughout, the numeral 1designates the valve stem of the ordinary form employed in connectionwith pneumatic-tires and surrounded by aprotccting sleeve 2, which maybe secured to the wheel felly in any suitable manner.

The ordinary check valve 3 is positioned in the end of the valve stem,and the extremity of the valve stem is reduced and threaded, as shown at4, for engagement in the lower threaded end 5 of the chamber 6, theprotecting sleeve 2 surrounding and protecting the connected ends 'ofthe valve stem'and chamber.

Vithin the lower end of the chamber 6 is positioned the washer 7,,preferably formed of lead, but which may be constructed of any pliablemetal or alloy, or other suitable material. The end of the valve stem 1is engaged against the washer 7 and the stop member 8, having its uppereudopen, is threaded in thewa sher'7 and has its closed upper endengaged against the end of the stem of the check valve 3, to retain saidvalve in open position. The stop member 8 is of, such size that the wallthereof is spaced from the interior of the valve stem 1 and the stopmember 8 is provided in one wall thereof with the opening 9 to allow theair from the stem 1 to enter the chamber 6. Within the lower end of thechamber 6 is positioned the diaphragm 10, which is held in position bythe ring 11, which engages the edge of the diaphragm and retains thesame against the end of the main portion of the cylinder, it beingunderstood that the lower end of the cham her is reduced in diameter, asclearly shown on the drawings. The ring 11 is held in proper position bymeans of a second ring '12, which is provided with the exterior threads13 engaged with the threaded inpositioned within the thimble 15 and hasone end engaged against the closed end of said thimble, while theopposite end of the spring is engaged against the lower end of the screw18, which is threaded through the plug 19, threaded in the upper openend of the chamber 6 and provided with the flange 20 to limit the inwardmovement of said plug. The screw 18 has the roughened head by means ofwhich the screw may be readily rotated in either direction to regulatethe tension of the spring17, as will belater clearly apparent. The screw18 is also provided with the stop collar 22 and set screw 23, by meansof which the stop collar 22 may be secured at any point along the screw17 to limit inwardmovement of said; screw.

The threaded bore 24 extends longitudinally through the screw 18,and'within this threaded bore is engaged the small screw 25, which hasthe stop nut 26 upon its upper end while the coil spring 27 is securedby one end to the lower end of the screw 25, the lower end of the coilspring 27 being adapted,

to be compressed at times by engagement therewith of the closed end 16of the thimble 15a. her 6 and extending longitudinally thereof, is acylinder.28, the upper end of which terminates about mid-way of thelength of the main portion ofthe chamber 6, while the lower end of thecylinder 28 is about on aline with the'lower extremity of the reducedend of said chamber. The'air passage 29 through the adjacent walls ofthe main portion of the chamber '6 and the cylinder 28, allows thecompressed air to travel from the chamber 6,to the cylinder 28, it beingunderstood that this passage-is below the diaphragm 10.

Within the cylinder 28 is a, check valve 30, similar to the check valve3 in the valve stem 1, said check valve 30 being normally seated uponthe valve seat 30 in the upper end of the cylinder 28. It will also beunderstood that the lower end of the cylinder 28 is closed, while theupper end thereof is open, and the stem of the check valve 30 extendsslightly above the open upper end of the cylinder 28 and into the loweropen end ofthe second cylinder 31, the upper end of the-second cylinderbeing closed and the wall of said second cylinder being provided withthe air escape opening 32.

The second cylinder 31 is secured to the plug 19 by means of the screw33, the head of which is opposite the air escape opening 32, thus makingit possible to readily position or remove the second cylinder. It willbe understood that-the lower end of the second cylinder and the upperend of the first cylinder are suitably connected to form an air-tightjoint, as shown at 34.

Thechamber 6 and second cylinder 31 are provided with communicatingopenings in their adjacent side's,as shown at 35, and the I stud 36secured to the thimble ,15 adjacent the upper edge thereof projectsthrough the openings 35. The purpose of the stud will be laterunderstood. Within the lower end of the second cylinder 31, but abovethe Secured to the outer face of the chamopening 35 therein, is securedthe lip 37, which has the parallel depending lugs 38 between which ispivoted the rock arm 39 by means of the pivot pin 40. The rock arm 39has one end directed downwardly below the openings 35 and adaptedfor'engagement by the stud 36 when the thimble 15 is in its uppermostposition. When the ever, the stud 36 is engaged against the horizontalarm of the L-shaped slide member 41, which arm is in turn engagedagainst the end of the stem of the check valve 30. The vertical arm ofthe L-shaped slide member 41 is normally engaged against the straightend of the rock arm 39.

From the above description, taken in connection with the accompanyingdrawings, it will be evident that the compressed air from within thetire will press against the under face of the diaphragm 10, forcing thethimble 15 upwardly, and when the parts are properly adjusted and theproper pressure is present within the tire, the thimble will be held ina normal or neutral position with the stud 36 between the end of therock arm 39' and the horizontal portion of the L- shaped slide member41-, thus permitting the check valve.'30 to remain in closed position.Should the pressure within the tire decrease, owing to a puncture or anyother cause, the coil spring 17 will overcome the pressure against theunder face of the diaphragm 10 and force the thimble 15 downwardlyagainst said diaphragm, thus causing the stud 36 to press downwardlyupon the horizontal portion of the L-shaped slide member 41, and therebyopen thecheck valve 30 and permit the air to travel through the cylinder28 to the second cylinder 31, pass the lip 37 and out to the atmosphereby means of the escape opening 32, thereby giving an audible signal.Should there be an excessive amount of pressure in the tire and againstthe under face of the diaphragm 10, the thimble 15 will be forcedupwardly to its uppermost position against the tension of the spring 17,and also the spring 27. When the thimble assumesthis position, the stud36 engages the depending end of the rock arm 39 and causes the same torock upon the pivot pin 40 and force the slide member 41 downwardly, thehorizontal portion of said slide member 41 opening the check valve 30,thus permitting the air to pass said check valve, enter the secondcylinder 31 and travel past the lip 37 to the atmosphere by means ofthe'opening 32 tocome the pressure against the under face of thediaphragm 10 and return the thimble thimble 15 is in its lowermostposition howtight.

ing the screws 18 and 25. For instance,a.

pneumatic tire which is built for use with an air pressure of sixtypounds, should not be run with a pressure lower than thirty-five poundsor higher than sixty-five pounds, therefore, wheii'any device isemployed in connection with a tire of this character, the

screws 18 and 25 are adjusted so that when the pressure in the tiredecreases below thirty-five pounds, the spring 17 will force the thimbledownwardly until the stud 36 presses downwardlv upon the horizontalportion of the slide member 41 to open the check valve 30, as previouslydescribed. Likewise, when the pressure within the tire increases abovesixty-five pounds, the thimble 15 will be forced upwardly against thetensionof the spring 17 and the spring 27 until the stud 36 engages thedepending end of the rock arm 89, thus forcing the arm to swing upon itspivot and move the slide member 41 downwardly to open the check valve'30, as also previously described. It will be evident, however, that aslight rotation of the screws 18 and 25 will adjust the device to giveits signal or allowthe escape of the excessive amount of air when thepressure is too high, as desired. It will further be evident. that byrotating the screw 25 a sufficient distance to properly compress thespring 27, operation of the device upon the increase of pressure may beavoided should occasion require.

While I have described my device as employed upon a pneumatic. tire, itwill be evident that the same may be used in connection with compressedair storage tanks for compressed air engines and infact may be employedin connection with various devices where it is required to retaincompressed air and prevent the pressure of the air from increasing ordecreasing beyond predetermined points.

It will further be evident that while I have shown the preferred form.of the device, I do .not wish to be limited to this specificconstruction, as minor changes may be made in various parts of in thescope of the appended claims without departing from the spirit of myinvention.

The diaphragm 10 may be formed of any suitable material, but ispreferably constructed of rubber, or other soft, pliable,

flexible material which will offer very little resistance and which isnon-porous and air- It will be understood that when the pressureincreases above a predetermined point, the apparatus will operate toexhaust the excessive pressure within the tire, caused by carelessnessin inflating the tire or by the natural increase of pressure fromfriction the device with-' or heat. .In the former case, as soon as thedevice is secured upon the valve stem,

it will operate to exhaust the excessive pressure and if the pressurewithin the tire is suflicient, the audible signal will be given. In thissecond case, however, when the pressure is increased by the expansion ofair.

cau'sed'by heat and friction, the increase will be gradual andinsufficient to cause the audible signal to be given.

What is claimed is i 1. A pneumatic signal removably engaged with theend of a valve tube and "comprising a chamber, a sliding thimble Withinthe chamber, a cylinder carried by the chamber and having communicationtherewith, a second cylinder carried by the chamber and in alinementwith the first cylinder, the adjacent walls of the chamber-and thesecond cylinder being provided with registering openings, a stud carriedby. the thimble and projecting through the registering openings andintothe second chamber, a check valve carried by thefirst cylinder, thesecond cylinder having an air escape opening and a plate therein andlocated adjacent said opening, means for sliding the thimble in onedirection upon increase of the pressure within the valve stem, means forlimiting movement of the thimble in this-direction, means for slidingthe thimble invan opposite direction upon a decrease of the pressure inthe valve stem, meansfor limiting movement of the thimble in thisdirection, and means carried by the second cylinder for operating thecheck valve in the first cylinder to permit air to travel from thefirstcylinder to the second cylinder and pass the plate to theatmosphere by means of the air escape opening to give a signal uponmovement of the sliding thimble.

2. A pneumatic signal comprising the combination with a valve controlledtube, of a chamber positioned on the end of the 1 tube and communicatingtherewith, a cylinder carried by the chamber and communicating with oneend thereof, a check valve in the cylinder, a second cylinder carried bythe chamber and in alinement with the first cylinder, said cylindersbeing connected at their open ends, the second cylinder having an airescape opening, a plate positioned in the second cylinder below the airescape opening, a rock arm pivoted to the plate and having a dependingend, a right angled slide member having one arm engaged against thestraight end of the rock arm,

. the other arm of the slide member being engaged against the checkvalve in the first cylinder, a thimble within the chamber, a studcarried by the thimble and projecting into the second cylinder, saidstud being normally spaced between the rock arm and the slide. member,means carried by the chamber for forcing the thimble downwardly upondecrease of the pressure within the tube, the stud being adapted toengage the slide member to force the same downwardly and open the checkvalve to give the signal upon downward movement of the thimble, meansfor forcing the thimble upwardly and causing the stud to engage thedepending end of the rock arm to operate the slide member and give thesignal upon an increase ofthe pressure above a predetermined point, andmeans for controlling movement of the thimble.

3. A pneumatic signal removably engaged with the end of a valve tube andcomprising a chamber, a sliding thimble within the chamber, a cylindercarried by the chamber and having communication therewith, a sec- 0ndcylinder in alinement with the first cylinder and communicating with-thesame, the chamber and second cylinder having registering openingsforming communication between said chamber and second cylinder, a checkvalve carriedby the first cylinder, the second cylinder having an airescape opening and a plate adjacent said opening and within thecylinder, a pivoted membercarried by the plate, a slidable memberbetween the pivoted member and the check valve in the first cylinder,andmeans carried by the sliding thimble and projecting i'nto the secondcylinde'r'for engagement with the slidable member when the thimble ismoved in one direct-ion upon decrease of pressure within the valve stem,said thimble being adapted to be moved in an opposite directionu-ponincrease of the pressure, the means carried by the thimble being adaptedto engage the pivoted member when the thimble is moved in thelastmentioned directiomthe signal being given opening the check valve inthe first cylinder to permit air to travel from said first cylinder tothe second cylinder and pass the plate to the atmosphere by means of theair escape opening, and means for resiliently retaining the thimbleinnormal position.

4. A pneumatic signal comprising the combination with a valve controlledtube, of a chamber positioned on the end of the tube by the slidablemember and communicating therewith, a cylinder carried by the chamberand communicating with one end thereof, a check valve in the cylinder, asecond cylinder carried by the chamber and removably engaged with oneend of the first cylinder, said cylinders having their connected endsopen to form communication between said cylinders, the second cylinderhaving an air escape opening, a plate carried by the second cylinderbelow the air escape opening, a right angled rock member pivoted by oneof its arms to the plate while its other arm depends from the first armadjacent the chamber, the chamber and second cylinder having registeringopenings forming communication between said chamber and cylinder, thefree end of the depending arm of the right angled rock member extendingbelow said registering openings, :1 right angled slide member having itslong arm engaged against the first mentioned arm of the rock member, theother arm of the slide member being engaged against the check valve inthe first cylinder, a thimble within the chamber, a stud carried bythe-thimble and projecting into the second cylinder, said stud beingnormally spaced between the depending arm of the rock member and one armof the slide member, means carried by the chamber for forcing thethimble downwardly upon decrease of the pressure within the tube, thestud being adapted to engage the slide member to force the samedownwardly and open the check valve to give the signal upon downwardmovement of the thimble, means for forcing the thimble upwardly andcausing the stud to engage the depending arm of the rock member tooperate the slide member and give the signal upon an increase of thepressure above a predetermined point, and means for controlling movementof the thimble.

In testimony whereof I hereunto afiix my signature in the presence oftwo witnesses.

JOSEPH B. POLO. VVitnesses:

E. E. WALSETH, J. A. THRONSON.

